The growth rate of boys and girls: bone age

They measure a girl

Why some children grow more than others. Weights and growth measures of children

The bone age does not always coincide with the real age of the child, so there are some taller and others shorter with respect to their chronological age. The rate at which the skeleton grows does not follow a fixed pattern and varies from person to person. It is believed to be an inherited trait, as many parents concerned about their child’s height are surprised by a late stretch and recall that they, too, experienced a similar growth pattern .

How old will my child be?

They measure a girl

To find out if the bone age is late or early, the pediatrician usually requests an  X-ray of the left hand and wrist , where the amount of cartilage that is still available is appreciated. When the cartilage closes, the bone can no longer be stretched. Advancement or retardation of bone age is a parameter that is calculated by observing the calcification of the  bones  in this area, which allows us to establish their maturation and, therefore, their approximate age.

As long as there are no other related diseases (heart disease, celiac disease or growth hormone deficiency) that can influence growth , children usually reach the right height due to their genetic inheritance , although this may occur earlier or later than expected. . To find out how tall you will be, there are several formulas.

One of them is the ‘ target size’ : father’s size + mother’s size + 13/2 = target size. In the case of male children, 13 is added to the sum of the parents’ sizes and in the case of women, 13 is subtracted from the same sum.

Another method consists of calculating the “projected height” , following on a graph of percentiles, the percentile by which a boy or a girl grows, until the age of 18 years. There are also other calculations that take into account chronological age, height, bone age, growth rate in the last year, and the degree of pubertal development. The margin of error is 2 to 4 cm. With this method, the final height can be predicted with a probability of success between 80 and 95 percent.

The results of these formulas may vary a few centimeters higher or lower because the genetic makeup of one of your parents may have influenced more in your final height. In addition, these calculations require adequate health and nutrition conditions for growth to occur normally.

When do the growth peaks occur?

During the first year of life and at puberty, the growth rate is more spectacular. At puberty, the peak occurs at age 12 in girls and at 14 in boys , reaching 20 percent of total growth. Although there are differences between both sexes that will mark the final height, since growth in girls is shorter and more intense, and in boys, more gradual and prolonged. Therefore, in the end, men will outnumber women by about 13 centimeters.

In addition to height, body mass also doubles and, while they develop twice as much muscle and skeleton as girls, they tend to accumulate more fat.


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